Published online before print August 7, 2006, doi: 10.1161/CIRCULATIONAHA.106.626143
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
(Circulation. 2006;114:654-661.)
© 2006 American Heart Association, Inc.
Imaging |
Quantitative Assessment of Left Ventricular Size and Function
Side-by-Side Comparison of Real-Time Three-Dimensional Echocardiography and Computed Tomography With Magnetic Resonance Reference
From the University of Chicago, Chicago, Ill (L.S., V.M.-A., L.W., R.M.L.); Public Hospital Elisabethinen, Linz, Austria (J.N., C.E., R.S.-M., H.-J.N.); and TomTec, Unterschleisheim, Germany (F.S., C.G., G.S.).
Correspondence to Lissa Sugeng, MD, University of Chicago, MC5084, 5841 S Maryland Ave, Chicago, IL 60637. E-mail lsugeng{at}medicine.bsd.uchicago.edu
Received March 9, 2006; revision received June 13, 2006; accepted June 14, 2006.
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Background— Cardiac CT (CCT) and real-time 3D echocardiography (RT3DE) are being used increasingly in clinical cardiology. CCT offers superb spatial and contrast resolution, resulting in excellent endocardial definition. RT3DE has the advantages of low cost, portability, and live 3D imaging without offline reconstruction. We sought to compare both CCT and RT3DE measurements of left ventricular size and function with the standard reference technique, cardiac MR (CMR).
Methods and Results— In 31 patients, RT3DE data sets (Philips 7500) and long-axis CMR (Siemens, 1.5 T) and CCT (Toshiba, 16-slice MDCT) images were obtained on the same day without ß-blockers. All images were analyzed to obtain end-systolic and end-diastolic volumes and ejection fractions using the same rotational analysis to eliminate possible analysis-related differences. Intertechnique agreement was tested through linear regression and Bland-Altman analyses. Repeated measurements were performed to determine intraobserver and interobserver variability. Both CCT and RT3DE measurements resulted in high correlation (r2>0.85) compared with CMR. However, CCT significantly overestimated end-diastolic and end-systolic volumes (26 and 19 mL; P<0.05), resulting in a small but significant bias in ejection fraction (–2.8%). RT3DE underestimated end-diastolic and end-systolic volumes only slightly (5 and 6 mL), with no significant bias in EF (0.3%; P=0.68). The limits of agreement with CMR were comparable for the 2 techniques. The variability in the CCT measurements was roughly half of that in either RT3DE or CMR values.
Conclusions— CCT provides highly reproducible measurements of left ventricular volumes, which are significantly larger than CMR values. RT3DE measurements compared more favorably with the CMR reference, albeit with higher variability.
Key Words: imaging • echocardiography • magnetic resonance imaging • tomography
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
The evaluation of left ventricular (LV) function is an indispensable component of routine clinical cardiology practice. For decades, 2D echocardiography has been the main noninvasive imaging modality used to evaluate LV function. However, the relatively low reproducibility and inaccuracy of this methodology have been attributed to the inadvertent use of foreshortened views of the left ventricle and the reliance on geometric modeling. In an attempt to overcome these limitations, alternative techniques based on 3D reconstruction from multiple planes1–4 have been developed and tested. This methodology, albeit time-consuming and prone to artifacts, has shown promise for more accurate assessment of LV function.3,5–8 More recently, real-time 3D echocardiographic (RT3DE) technology, which allows fast acquisition of dynamic pyramidal data sets that encompass the entire left ventricle, has become widely available. Several studies have demonstrated the improved accuracy of RT3DE measurements of LV volume,9–14 despite the continued reliance on endocardial tracing in selected planes and geometric modeling.12,15 To circumvent these limitations, a novel approach based on the detection of dynamic endocardial surface in 3D space was recently developed and tested.16,17 We showed that by fully exploiting the volumetric information contained in RT3DE data sets without the need for either plane selection or geometric modeling, this technique provides accurate objective evaluation of LV function.18 A similar approach was recently implemented in commercial software that is currently available to RT3DE users.19,20
Clinical Perspective p 661
At the same time, MRI technology has gone through technological leaps that brought it to speeds that allow dynamic imaging of the beating heart. Combined with excellent spatial and contrast resolution and the built-in multislice imaging ability, cardiac MR (CMR) has quickly gained popularity and is currently considered the reference technique for LV size and function measurements. Nevertheless, the current standard for CMR assessment of LV function is based on analysis of stacks of short-axis slices of the ventricle. This methodology is increasingly recognized as less than ideal because of (1) the need to select slices to be included in the analysis, which is difficult near the LV base and apex; (2) poor endocardial definition near the apex as a result of partial-volume artifacts, the main source of intermeasurement variability; and (3) the use of spatially fixed slices that disregards LV systolic shortening. Therefore, better reference techniques are needed that would become the future gold standard of LV function. A recent study suggested that analysis of radial long-axis CMR images could potentially minimize these limiting factors and thus provide a better reference.21
CT also has recently undergone major technological developments that currently allow quantification of LV function. The unprecedented quality of cardiac CT (CCT) images, which offer superb endocardial definition optimal for boundary detection, suggests that this modality could potentially constitute a more reproducible reference technique. However, the few studies aimed at validating these measurements against a CMR reference22–26 or other techniques26–28 have not unequivocally established their accuracy. Several studies found that LV volumes were overestimated and ejection fraction (EF) was underestimated by CCT and suggested the intermodality differences in acquisition and analysis strategies as the main source of this discrepancy.22,25,26
Accordingly, to allow intermodality comparisons while eliminating such differences as a potential source of error, we implemented volumetric quantification of LV function in prototype software that allows analysis of radial long-axis CMR and CCT images and RT3DE data sets. The aim of this study was to compare side-by-side indices of LV function derived through analysis of these 3 types of images by using this rotational approach. To achieve this goal, we studied the agreement between CCT- and RT3DE-derived LV function indices against the CMR reference and the reproducibility of these indices for each of the 3 modalities.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Population
Thirty-one patients (17 men, 14 women; age, 60±15 years) were studied. These patients were selected from 33 consecutive patients referred for clinically indicated CT angiography who were scanned for transthoracic 2D acoustic windows that allowed adequate endocardial visualization. Patients with atrial fibrillation or other cardiac arrhythmias or dyspnea precluding a 10- to 15-second breathhold and patients with implanted pacemakers or defibrillators or with claustrophobia were excluded. Also, patients were excluded if they could not undergo CCT imaging because of renal dysfunction (creatinine >1.3 mg/dL) or known allergy to iodine. Of these 31 patients, 9 had normal hearts, 14 had coronary artery disease, 7 had dilated ventricles, and 1 had apical hypertrophic cardiomyopathy. CMR, CCT, and RT3DE images were performed in each patient on the same day. Heart rate was monitored continuously throughout image acquisition by all 3 modalities. No ß-blockers were used to lower the heart rate before CCT imaging. Written informed consent was obtained from all patients.
CMR Imaging
CMR images were obtained with a 1.5-T Sonata scanner (Siemens, Forchheim, Germany) with a phased-array cardiac coil. ECG-gated localizing spin-echo sequences were used to identify the long axis of the left ventricle and to allow imaging in 6 planes rotated around the long axis at 30° steps. Steady-state free precession dynamic gradient-echo mode was then used to acquire dynamic cine loops (20 frames per cardiac cycle) of radial long-axis views of the ventricle (10-mm slice thickness; 1.4- to 1.8-mm in-slice resolution) and stacks of short-axis images from the AV ring to the apex (10-mm slice thickness, no gaps). All images were acquired during 10- to 15-second breathholds and stored digitally for offline analysis of LV function.
CCT Imaging
CCT images were obtained with a Toshiba 16-slice multidetector scanner (Toshiba, Otawara, Japan). Nonionic iodinated contrast agent (Iomeron) was injected into the antecubital vein (140 mL at 3.5 mL/s) and was followed by a 50-mL saline chaser bolus. Image acquisition was triggered by the appearance of contrast in the aortic root and was performed during a single breathhold at end-inspiration preceded by mild hyperventilation. Imaging parameters included 250-ms gantry rotation time with 5 mm per rotation and tube voltage of 120 kV with currents of 300 mA. Scan data were then reconstructed at 0.5-mm slice thickness and 0.5-mm in-slice resolution with retrospective ECG gating and a smooth-tissue filter kernel from early systole (0% of the RR interval) to late diastole (90% of the RR interval) at 10% steps, resulting in 10 phases of the cardiac cycle. For each phase, the reconstructed data were stored digitally. Then, for each phase, 6 planes rotated around the long axis of the left ventricle at 30° steps were selected and used for analysis of LV function.
RT3DE Imaging
RT3DE imaging was performed from the apical window with the patient in the left lateral decubitus position with a SONOS 7500 scanner (Philips, Andover, Mass) equipped with a fully sampled matrix array transducer (X4) in the harmonic mode. To include the entire LV cavity within the pyramidal scan volume, data sets were acquired using the wide-angled mode, wherein 4 wedge-shaped subvolumes (93x21°) were acquired during a single breathhold. Acquisition of each subvolume was triggered by the ECG R wave of every other heartbeat (total of 8 heartbeats) to allow sufficient time for each subvolume to be stored.11 Six automatically selected long-axis planes rotated around the long axis of the left ventricle at 30° steps were subsequently used to analyze LV function.
Image Analysis
RT3DE data sets were analyzed with 4D-LV Analysis software (TomTec Imaging Systems, Unterschleisheim, Germany). Radial long-axis images obtained from CMR and CCT data were analyzed with prototype software (TomTec) based on the same principle of rotational analysis. In every slice, LV endocardial contours were traced semiautomatically frame by frame, with the papillary muscles and trabeculae included in the LV cavity. These contours were corrected manually when necessary and then used to reconstruct for each phase of the cardiac cycle the endocardial surface in the 3D space. These reconstructed surfaces were used to calculate LV volume over time throughout the cardiac cycle. Each volume curve was analyzed to obtain end-diastolic (EDV) and end-systolic (ESV) volumes that were identified as the maximum and minimum values, and EF was computed as follows: (EDV–ESV)/EDV. Endocardial tracing and volume measurements were performed in a random order by an investigator experienced in the interpretation of cardiac images who was blinded to the results of all prior measurements. In 10 randomly selected patients, image analysis was repeated a month later by the same primary reader and by an additional investigator to determine the reproducibility of LV volume and EF measurements for each imaging modality. In addition, commercial software was used to analyze the short-axis CMR images using standard semiautomated endocardial boundary detection and calculation of EDV, ESV, and EF by the method of disks (Argus, Siemens, Forchheim, Germany).
Statistical Analysis
All LV volume and EF values were expressed as mean±SD. The relationship between each technique, CCT and RT3DE, and CMR was evaluated with linear regression analysis with Pearson’s correlation coefficient. The agreement between CCT and RT3DE measurements and CMR reference values was evaluated through the use of Bland-Altman analysis29 by calculating the bias (mean difference) and the 95% limits of agreement (2 SD around the mean difference). The difference between values yielded by each modality and the CMR reference values was plotted against their mean to avoid artificial trends.30 The significance of the biases was tested through the use of paired t tests with a 2-sided alternative. Similarly, CMR measurements obtained from radial acquisitions were compared with those derived from short-axis CMR images. Values of P<0.05 were considered significant.
The reproducibility of the CMR-, CCT-, and RT3DE-derived measurements of EDV and ESV and EF was evaluated by calculating the intraobserver and interobserver variability of each technique, which was defined as the absolute difference between the corresponding repeated measurements expressed in percent of their mean. Variability values obtained for each index in each patient for each imaging modality were then averaged over the entire group of patients and presented as mean±SD.
The authors had full access to the data and take responsibility for their integrity. All authors have read and agree to the manuscript as written.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
No significant changes were noted in heart rate during image acquisition by either modality. The time required for image analysis of each data set (including data retrieval) was &20 to 40 minutes on a Pentium 4 personal computer. Manual corrections were necessary to optimize the position of the endocardial boundaries in all patients for all 3 imaging modalities, but the required corrections were more extensive for RT3DE than for CCT and CMR.
Figure 1 (left) shows an example of radial long-axis images obtained at end diastole in a patient with normal wall motion from the 3 imaging modalities: CMR (top), CCT (center), and RT3DE (bottom), with the corresponding reconstructed LV endocardial surfaces (middle) and volume-over-time curves (right). Similar to CMR, the CCT-derived curve had the expected shape that reflected the ejection and filling phases of the cardiac cycle. The RT3DE-derived curves also had a similar shape despite the less detailed endocardial delineation. Figure 2 shows an example of data obtained in a patient with a severely enlarged left ventricle. In this example, the shape of the LV volume curves is preserved, as demonstrated by all 3 imaging modalities. However, the volumes are 2 to 3 times larger than those seen in Figure 1.
|
|
Figure 3 shows the results of linear regressions analysis for CCT (top) and RT3DE (bottom) measurements of LV volumes and EF versus the CMR reference values. Both modalities correlated well with CMR (r2=0.93 to 0.96) except for CCT-derived EF (r2=0.85). Figure 4 summarizes the results of Bland-Altman analysis for CCT (top) and RT3DE (bottom) measurements of LV volumes and EF versus the CMR reference values. CCT measurements resulted in significantly overestimated values of both EDV and ESV, as reflected by biases of 26 and 19 mL, respectively. EF was slightly but nevertheless significantly underestimated as reflected by a bias of –2.8%. In contrast, RT3DE measurements resulted in slightly underestimated values of both EDV and ESV, as reflected by nonsignificant biases of –5 and –6 mL, respectively, and virtually no bias (0.3%). The 95% limits of agreement with CMR were tighter for CCT than RT3DE for both EDV (42 versus 52 mL) and ESV (50 versus 52 mL) but not for EF (13% versus 8%).
|
|
The Table shows the interobserver and intraobserver variability in EDV, ESV, and EF measurements for all 3 imaging modalities. CCT seemed to be the most reproducible technique, as reflected by the interobserver and intraobserver variability values that were lower than those of CMR for all measured indices. RT3DE seemed to be the least reproducible of the 3 techniques as reflected by the highest variability values with the exception of intraobserver variability of ESV and consequently EF, which were similar for both the RT3DE and CMR techniques.
|
Figure 5 shows the results of the comparisons between CMR measurements of LV volumes and EF derived from the radial acquisition versus the traditional short-axis stacks. All 3 variables showed high correlations (r2=0.95 to 0.98). Bland-Altman analysis resulted in small negative biases in EDV (–4 mL), ESV (–1 mL), and EF (–1.8%). The 95% limits of agreement were 38 mL for EDV, 30 mL for ESV, and 10% for EF.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
In routine clinical cardiology practice, critical decision making such as defibrillator implantation, biventricular pacing, treatment of congestive heart failure is based heavily on EF. Accordingly, it is extremely important that this index be measured accurately and reproducibly. For decades, the 2D nature of ultrasound imaging has affected the quantification of LV size and function by errors that stemmed mainly from foreshortened views and inaccurate geometric modeling. The inadequacy of this methodology has been demonstrated by several investigators who compared 2D echocardiographic measures against multislice CMR reference.15,18,20,31 The recent development of live volumetric ultrasound imaging promises to provide a quick, inexpensive, portable, and accurate alternative for LV size and function analysis. In view of the rapidly growing popularity of noninvasive coronary angiography with multidetector "spiral" CT scanners, which are capable of continuous volumetric imaging of the beating heart with unparalleled endocardial definition allowing for highly reproducible quantification of ventricular size and function, this modality has been increasingly referred to as a potential tool for the combined assessment of coronary anatomy, myocardial perfusion, and LV function. It is imperative, however, that the ability of both volumetric imaging techniques to provide accurate indices of LV size and function be tested thoroughly before widespread clinical use. This study is the first to validate side-by-side RT3DE- and CCT-derived indices of LV size and function with reference values obtained from radial long-axis CMR images that offer significant advantages over the conventional short-axis images, including no need to exclude slices that contain LV outflow tract, more uniform endocardial definition from base to apex, and optimal visualization of LV systolic shortening within the imaging plane. Furthermore, the use of the same rotational approach to analyze images obtained with all 3 modalities allowed us to minimize possible analysis-related differences as a source of error.
Our results confirmed the linear relationship between both volumetric imaging techniques and the CMR reference, as reflected by the high correlation coefficients obtained for all measured indices (Figure 3). CCT measurements were found to be highly reproducible, as reflected by minimal interobserver and intraobserver variability in all measured indices (see the Table). However, CCT significantly overestimated LV volumes compared with the CMR values, resulting in a small but significant negative bias in the calculated EF (Figure 4). Although several previous studies have demonstrated good agreement between CCT and CMR evaluation of LV function,23–25 others reported findings similar to ours.22,26 Grude and coworkers22 reported positive biases of 10% and 38% in EDV and ESV, respectively, resulting in a negative bias in EF that was 3 times larger than measured in our study (–8.5%). Salm et al26 found a smaller negative bias in EF (–1.5%) but did not report results for LV volumes. Both groups made positive conclusions with regard to the agreement between the 2 techniques by interpreting the statistically significant small biases in the measured EF as clinically insignificant.26 However, the differences in LV volumes noted in our study are large enough to warrant future studies aimed at obtaining normal LV volume values specifically for CCT.
The relatively low temporal resolution of the reformatted CCT data, which is typically reconstructed at 20 phases of the cardiac cycle, has previously been suggested as a possible explanation for overestimated LV volumes.26 Although such undersampling could theoretically explain overestimated ESV by missing the fast transition from ventricular contraction to filling, it is not likely to result in overestimated EDV because there is very little change in LV volume over a relatively long time in late diastole. To test this hypothesis, in this study, we reconstructed CCT data at even lower temporal resolution (10 phases of the cardiac cycle) and found that both EDV and ESV were overestimated to a similar degree, as reflected by respective biases of 26 and 19 mL. It also is possible that rapid injection of a large volume of iodine contrast solution could have resulted in transient changes in preload and negative inotropic effects. In addition, acute changes in blood pressure in response to the power injection of contrast could not be ruled out because arterial blood pressure was not monitored continuously. Alternative explanations for this finding could be the intermodality differences in the ability to visualize endocardial boundary details and to include or exclude trabeculae from the LV cavity. One might also suggest that ß-blockers, which are used routinely with CCT imaging, could result in increased LV volumes and thus could impede direct comparisons between CCT and other imaging modalities that do not use ß-blockers. However, to avoid this issue, ß-blockers were not used in this study.
As expected, because of the relatively low spatial resolution of ultrasound imaging limiting endocardial visualization, RT3DE-derived LV volume values are subject to wider intermeasurement variability compared with CCT and CMR. Interestingly, however, despite this variability, RT3DE volume estimates were in agreement with the CMR reference, unlike the previous reports of significant biases in RT3DE-based LV indices compared with CMR.13,18 However, in that study, the CMR reference values were obtained from stacks of short-axis slices with their known limitations, thus rendering analysis-related differences impossible to rule out. By applying the same rotational approach, we eliminated this bias and revealed good agreement with CMR reference values and decreased underestimation of RT3DE-derived volume data.
In addition, one might view the use of the unconventional radial CMR acquisitions as somewhat problematic because most clinical laboratories and published articles routinely calculate LV volumes by applying the method of disks to stacks of short-axis images. Although our choice of reference technique was part of the study design in an attempt to apply uniform analysis techniques to images from 3 modalities and overcome the known limitations of the traditional CMR methodology, we acquired CMR images using both approaches and compared the results in every patient. These comparisons showed close agreement between the 2 CMR techniques, which justified the deviation from the accepted standard.
In addition to the relatively low temporal resolution of the volumetric techniques we tested in this study, the small number of imaging planes could be viewed as an additional limitation, which might have limited the accuracy of endocardial surface reconstruction. However, in a previous study,32 6 planes were found to be sufficient to adequately assess global LV function. The known factors that limit the use of RT3DE imaging in daily practice include the relatively low spatial resolution, limited sector size, and large transducer footprint. Further miniaturization, advances in ultrasound technology, and increasing sector size may overcome these limitations. The addition of contrast and triggered RT3DE acquisition also may improve border definition and thus the accuracy of LV volume measurements.33
In summary, the results of this study confirmed that analysis of dynamic volumetric data, either CCT or RT3DE, allows meaningful measurements of LV size and function. With the rapid technological developments and the growing availability of fast volumetric imaging and analysis software, these measurements are likely to become part of routine clinical cardiology practice soon.
|
Acknowledgments |
|---|
Sources of Funding
This work was supported by an American Heart Association grant-in-aid to Dr Mor-Avi, the principal investigator.
Disclosures
None.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Gopal AS, King DL, Katz J, Boxt LM, King DL Jr, Shao MY. Three-dimensional echocardiographic volume computation by polyhedral surface reconstruction: in vitro validation and comparison to magnetic resonance imaging. J Am Soc Echocardiogr. 1992; 5: 115–124.[Medline] [Order article via Infotrieve]
2. King DL, Gopal AS, Sapin PM, Schroder KM, DeMaria AN. Three-dimensional echocardiography. Am J Card Imaging. 1993; 7: 209–220.[Medline] [Order article via Infotrieve]
3. Gopal AS, Schnellbaecher MJ, Shen Z, Boxt LM, Katz J, King DL. Freehand three-dimensional echocardiography for determination of left ventricular volume and mass in patients with abnormal ventricles: comparison with magnetic resonance imaging. J Am Soc Echocardiogr. 1997; 10: 853–861.[CrossRef][Medline] [Order article via Infotrieve]
4. Jiang L, Vazquez de Prada JA, Handschumacher MD, Vuille C, Guererro JL, Picard MH, Joziatis JT, Fallon JT, Weyman AE, Levine RA. Quantitative three-dimensional reconstruction of aneurysmal left ventricles: in vitro and in vivo validation. Circulation. 1995; 91: 222–230.
5. Hozumi T, Yoshikawa J, Yoshida K, Akasaka T, Takagi T, Yamamuro A. Three-dimensional echocardiographic measurement of left ventricular volumes and ejection fraction using a multiplane transesophageal probe in patients. Am J Cardiol. 1996; 78: 1077–1080.[CrossRef][Medline] [Order article via Infotrieve]
6. Mele D, Maehle J, Pedini I, Alboni P, Levine RA. Three-dimensional echocardiographic reconstruction: description and applications of a simplified technique for quantitative assessment of left ventricular size and function. Am J Cardiol. 1998; 81: 107G–110G.[CrossRef][Medline] [Order article via Infotrieve]
7. Kupferwasser I, Mohr-Kahaly S, Stahr P, Rupprecht HJ, Nixdorff U, Fenster M, Voigtlander T, Erbel R, Meyer J. Transthoracic three-dimensional echocardiographic volumetry of distorted left ventricles using rotational scanning. J Am Soc Echocardiogr. 1997; 10: 840–852.[CrossRef][Medline] [Order article via Infotrieve]
8. Legget ME, Leotta DF, Bolson EL, McDonald JA, Martin RW, Li XN, Otto CM, Sheehan FH. System for quantitative three-dimensional echocardiography of the left ventricle based on a magnetic-field position and orientation sensing system. IEEE Trans Biomed Eng. 1998; 45: 494–504.[CrossRef][Medline] [Order article via Infotrieve]
9. Ota T, Fleishman CE, Strub M, Stetten G, Ohazama CJ, von Ramm OT, Kisslo J. Real-time, three-dimensional echocardiography: feasibility of dynamic right ventricular volume measurement with saline contrast. Am Heart J. 1999; 137: 958–966.[CrossRef][Medline] [Order article via Infotrieve]
10. Collins M, Hsieh A, Ohazama CJ, Ota T, Stetten G, Donovan CL, Kisslo J, Ryan T. Assessment of regional wall motion abnormalities with real-time 3-dimensional echocardiography. J Am Soc Echocardiogr. 1999; 12: 7–14.[CrossRef][Medline] [Order article via Infotrieve]
11. Sugeng L, Weinert L, Lang RM. Left ventricular assessment using real time three dimensional echocardiography. Heart. 2003; 89 (suppl 3): iii29–iii36.
12. Zeidan Z, Erbel R, Barkhausen J, Hunold P, Bartel T, Buck T. Analysis of global systolic and diastolic left ventricular performance using volume-time curves by real-time three-dimensional echocardiography. J Am Soc Echocardiogr. 2003; 16: 29–37.[CrossRef][Medline] [Order article via Infotrieve]
13. Kuhl HP, Schreckenberg M, Rulands D, Katoh M, Schafer W, Schummers G, Bucker A, Hanrath P, Franke A. High-resolution transthoracic real-time three-dimensional echocardiography: quantitation of cardiac volumes and function using semi-automated border detection and comparison with cardiac magnetic resonance imaging. J Am Coll Cardiol. 2004; 43: 2083–2090.
14. Jenkins C, Bricknell K, Hanekom L, Marwick TH. Reproducibility and accuracy of echocardiographic measurements of left ventricular parameters using real-time three-dimensional echocardiography. J Am Coll Cardiol. 2004; 44: 878–886.
15. Mor-Avi V, Sugeng L, Weinert L, MacEneaney P, Caiani EG, Koch R, Salgo IS, Lang RM. Fast measurement of left ventricular mass with real-time three-dimensional echocardiography: comparison with magnetic resonance imaging. Circulation. 2004; 110: 1814–1818.
16. Corsi C, Lang RM, Veronesi F, Weinert L, Caiani EG, MacEneaney P, Lamberti C, Mor-Avi V. Volumetric quantification of global and regional left ventricular function from real-time three-dimensional echocardiographic images. Circulation. 2005; 112: 1161–1170.
17. Corsi C, Saracino G, Sarti A, Lamberti C. Left ventricular volume estimation for real-time three-dimensional echocardiography. IEEE Trans Med Imaging. 2002; 21: 1202–1208.[CrossRef][Medline] [Order article via Infotrieve]
18. Caiani EG, Corsi C, Zamorano J, Sugeng L, MacEneaney P, Weinert L, Battani R, Gutierrez JL, Koch R, de Isla LP, Furlong K, Mor-Avi V, Lang RM. Improved semi-automated quantification of left ventricular volumes and ejection fraction using high-resolution real-time three-dimensional echocardiography: comparison with MRI. J Am Soc Echocardiogr. 2005; 18: 779–788.[CrossRef][Medline] [Order article via Infotrieve]
19. Gerard O, Billon AC, Rouet JM, Jacob M, Fradkin M, Allouche C. Efficient model-based quantification of left ventricular function in 3-D echocardiography. IEEE Trans Med Imaging. 2002; 21: 1059–1068.[CrossRef][Medline] [Order article via Infotrieve]
20. Jacobs LD, Salgo IS, Goonewardena S, Weinert L, Coon P, Bardo D, Gerard O, Allain P, Zamorano JL, de Isla LP, Mor-Avi V, Lang RM. Rapid online quantification of left ventricular volume from real-time three-dimensional echocardiographic data. Eur Heart J. 2005; 27: 460–468.[CrossRef][Medline] [Order article via Infotrieve]
21. Bloomer TN, Plein S, Radjenovic A, Higgins DM, Jones TR, Ridgway JP, Sivananthan MU. Cine MRI using steady state free precession in the radial long axis orientation is a fast accurate method for obtaining volumetric data of the left ventricle. J Magn Reson Imaging. 2001; 14: 685–692.[CrossRef][Medline] [Order article via Infotrieve]
22. Grude M, Juergens KU, Wichter T, Paul M, Fallenberg EM, Muller JG, Heindel W, Breithardt G, Fischbach R. Evaluation of global left ventricular myocardial function with electrocardiogram-gated multidetector computed tomography: comparison with magnetic resonance imaging. Invest Radiol. 2003; 38: 653–661.[Medline] [Order article via Infotrieve]
23. Juergens KU, Grude M, Maintz D, Fallenberg EM, Wichter T, Heindel W, Fischbach R. Multi-detector row CT of left ventricular function with dedicated analysis software versus MR imaging: initial experience. Radiology. 2004; 230: 403–410.
24. Mahnken AH, Katoh M, Bruners P, Spuentrup E, Wildberger JE, Gunther RW, Buecker A. Acute myocardial infarction: assessment of left ventricular function with 16-detector row spiral CT versus MR imaging: study in pigs. Radiology. 2005; 236: 112–117.
25. Mahnken AH, Koos R, Katoh M, Spuentrup E, Busch P, Wildberger JE, Kuhl HP, Gunther RW. Sixteen-slice spiral CT versus MR imaging for the assessment of left ventricular function in acute myocardial infarction. Eur Radiol. 2005; 15: 714–720.[CrossRef][Medline] [Order article via Infotrieve]
26. Salm LP, Schuijf JD, de RA, Lamb HJ, Vliegen HW, Jukema JW, Joemai R, van der Wall EE, Bax JJ. Global and regional left ventricular function assessment with 16-detector row CT: comparison with echocardiography and cardiovascular magnetic resonance. Eur J Echocardiogr. 2005; 7: 308–314.[Medline] [Order article via Infotrieve]
27. Dirksen MS, Bax JJ, de RA, Jukema JW, van der Geest RJ, Geleijns K, Boersma E, van der Wall EE, Lamb HJ. Usefulness of dynamic multislice computed tomography of left ventricular function in unstable angina pectoris and comparison with echocardiography. Am J Cardiol. 2002; 90: 1157–1160.[CrossRef][Medline] [Order article via Infotrieve]
28. Juergens KU, Grude M, Fallenberg EM, Opitz C, Wichter T, Heindel W, Fischbach R. Using ECG-gated multidetector CT to evaluate global left ventricular myocardial function in patients with coronary artery disease. AJR Am J Roentgenol. 2002; 179: 1545–1550.
29. Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986; 1: 307–310.[CrossRef][Medline] [Order article via Infotrieve]
30. Bland JM, Altman DG. Comparing methods of measurement: why plotting difference against standard method is misleading. Lancet. 1995; 346: 1085–1087.[CrossRef][Medline] [Order article via Infotrieve]
31. Chuang ML, Hibberd MG, Salton CJ, Beaudin RA, Riley MF, Parker RA, Douglas PS, Manning WJ. Importance of imaging method over imaging modality in noninvasive determination of left ventricular volumes and ejection fraction: assessment by two- and three-dimensional echocardiography and magnetic resonance imaging. J Am Coll Cardiol. 2000; 35: 477–484.
32. Tanabe K, Belohlavek M, Jakrapanichakul D, Bae RY, Greenleaf JF, Seward JB. Three-dimensional echocardiography: precision and accuracy of left ventricular volume measurement using rotational geometry with variable numbers of slice resolution. Echocardiography. 1998; 15: 575–580.[Medline] [Order article via Infotrieve]
33. Caiani EG, Coon P, Corsi C, Goonewardena S, Bardo D, Rafter P, Sugeng L, Mor-Avi V, Lang RM. Dual triggering improves the accuracy of left ventricular volume measurements by contrast-enhanced real-time 3D echocardiography. J Am Soc Echocardiogr. 2005; 18: 1292–1298.[CrossRef][Medline] [Order article via Infotrieve]
 |
|
 |
|
  V. Mor-Avi, L. Sugeng, and R. M. Lang Real-Time 3-Dimensional Echocardiography: An Integral Component of the Routine Echocardiographic Examination in Adult Patients? Circulation, January 20, 2009; 119(2): 314 - 329. [Full Text] [PDF]
|
|
|
|
 |
|
 T. Nishikage, H. Nakai, V. Mor-Avi, R. M. Lang, I. S. Salgo, S. H. Settlemier, S. Husson, and M. Takeuchi Quantitative assessment of left ventricular volume and ejection fraction using two-dimensional speckle tracking echocardiography Eur J Echocardiogr, January 1, 2009; 10(1): 82 - 88. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Marcucci, R. Lauer, and A. Mahajan New Echocardiographic Techniques for Evaluating Left Ventricular Myocardial Function Seminars in Cardiothoracic and Vascular Anesthesia, December 1, 2008; 12(4): 228 - 247. [Abstract] [PDF]
|
|
|
|
|
|
B. Jungwirth and G. B. Mackensen Real-Time 3-Dimensional Echocardiography in the Operating Room Seminars in Cardiothoracic and Vascular Anesthesia, December 1, 2008; 12(4): 248 - 264. [Abstract] [PDF]
|
|
|
|
 |
|
 R. C. Cury, K. Nieman, M. D. Shapiro, J. Butler, C. H. Nomura, M. Ferencik, U. Hoffmann, S. Abbara, D. S. Jassal, T. Yasuda, et al. Comprehensive Assessment of Myocardial Perfusion Defects, Regional Wall Motion, and Left Ventricular Function by Using 64-Section Multidetector CT Radiology, August 1, 2008; 248(2): 466 - 475. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A-C Pouleur, J-B le Polain de Waroux, A Pasquet, B L Gerber, O Gerard, P Allain, and J-L J Vanoverschelde Assessment of left ventricular mass and volumes by three-dimensional echocardiography in patients with or without wall motion abnormalities: comparison against cine magnetic resonance imaging Heart, August 1, 2008; 94(8): 1050 - 1057. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. De Castro, F. Faletra, E. Di Angelantonio, C. Conca, A. Marcantonio, M. Francone, D. Cartoni, F. Mirabelli, C. Gaudio, S. Caselli, et al. Tomographic Left Ventricular Volumetric Emptying Analysis by Real-Time 3-Dimensional Echocardiography: Influence of Left Ventricular Dysfunction With and Without Electrical Dyssynchrony Circ Cardiovasc Imaging, July 1, 2008; 1(1): 41 - 49. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Mor-Avi, C. Jenkins, H. P. Kuhl, H.-J. Nesser, T. Marwick, A. Franke, C. Ebner, B. H. Freed, R. Steringer-Mascherbauer, H. Pollard, et al. Real-time 3-dimensional echocardiographic quantification of left ventricular volumes multicenter study for validation with magnetic resonance imaging and investigation of sources of error. J. Am. Coll. Cardiol. Img., July 1, 2008; 1(4): 413 - 423. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W T Roberts, J J Bax, and L C Davies Cardiac CT and CT coronary angiography: technology and application Heart, June 1, 2008; 94(6): 781 - 792. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. D. Soriano, M. Hoch, A. Ithuralde, T. Geva, A. J. Powell, B. D. Kussman, D. A. Graham, W. Tworetzky, and G. R. Marx Matrix-Array 3-Dimensional Echocardiographic Assessment of Volumes, Mass, and Ejection Fraction in Young Pediatric Patients With a Functional Single Ventricle: A Comparison Study With Cardiac Magnetic Resonance Circulation, April 8, 2008; 117(14): 1842 - 1848. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N E MANGHAT, V RACHAPALLI, R V. LINGEN, A M VEITCH, C A ROOBOTTOM, and G J MORGAN-HUGHES Imaging the heart valves using ECG-gated 64-detector row cardiac CT Br. J. Radiol., April 1, 2008; 81(964): 275 - 290. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J L Hare, C Jenkins, S Nakatani, A Ogawa, C-M Yu, and T H Marwick Feasibility and clinical decision-making with 3D echocardiography in routine practice Heart, April 1, 2008; 94(4): 440 - 445. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C M TONGE, R C FERNANDEZ, and M T HARBINSON Current issues in nuclear cardiology Br. J. Radiol., April 1, 2008; 81(964): 270 - 274. [Full Text] [PDF]
|
|
|
|
 |
|
 A. M. Arruda-Olson, F. Bursi, Y. Gerber, R. H. May, V. L. Roger, and P. A. Pellikka Three-Dimensional Echocardiography for Evaluating Left Ventricular Function in Patients With ST Elevation Myocardial Infarction: A Pilot Study Mayo Clin. Proc., March 1, 2008; 83(3): 372 - 373. [Full Text] [PDF]
|
|
|
|
 |
|
 K. U. Juergens, H. Seifarth, F. Range, S. Wienbeck, M. Wenker, W. Heindel, and R. Fischbach Automated Threshold-Based 3D Segmentation Versus Short-Axis Planimetry for Assessment of Global Left Ventricular Function with Dual-Source MDCT Am. J. Roentgenol., February 1, 2008; 190(2): 308 - 314. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. N. Kirkpatrick, M. A. Vannan, J. Narula, and R. M. Lang Echocardiography in Heart Failure: Applications, Utility, and New Horizons J. Am. Coll. Cardiol., July 31, 2007; 50(5): 381 - 396. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. B. Mark, R. K. Patel, and A. G. Jardine Are we overestimating left ventricular abnormalities in end-stage renal disease? Nephrol. Dial. Transplant., July 1, 2007; 22(7): 1815 - 1819. [Full Text] [PDF]
|
|
|
|
|
|
R. Olszewski, J. Timperley, S. Cezary, M. Monaghan, P. Nihoyannopoulis, R. Senior, and H. Becher The clinical applications of contrast echocardiography Eur J Echocardiogr, June 1, 2007; 8(3): s13 - s23. [Full Text] [PDF]
|
|
|
|
|
|
T. J. Bunch, S. H. Hohnloser, and B. J. Gersh Mechanisms of Sudden Cardiac Death in Myocardial Infarction Survivors: Insights From the Randomized Trials of Implantable Cardioverter-Defibrillators Circulation, May 8, 2007; 115(18): 2451 - 2457. [Full Text] [PDF]
|
|
|
|
|
|
A. E. Weyman The Year in Echocardiography J. Am. Coll. Cardiol., March 20, 2007; 49(11): 1212 - 1219. [Full Text] [PDF]
|
|
|
|
|
|
P. Knaapen, T. Germans, J. Knuuti, W. J. Paulus, P. A. Dijkmans, C. P. Allaart, A. A. Lammertsma, and F. C. Visser Myocardial Energetics and Efficiency: Current Status of the Noninvasive Approach Circulation, February 20, 2007; 115(7): 918 - 927. [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||